Cartridge gain question

What does a person look for in the specs of a preamp to determine whether to buy a high, medium or low gain phono cartridge?
You look at the cartridge to determine how much gain your preamp needs
Please disregard my original post. I should have first searched the archives on this subject. I've since found a great explanation in an old thread.
KAB Acoustics has a really neat gain calculator that can be found here:

It takes a lot of the guess work out of these calculations.
Rockyboy; here's a simple chart showing approximate gain needed for a range of cartridge output voltages. (Modified from KAB website.) Below the chart is a link to the KAB gain calculator. It also provides a way to determine phono gain when only sensitivity is provided.


Chart of Typical Gain Values:

Cart Output..........Phono Gain
0.15mV or less.....>70dB


PS: I was going to reply to your question last night but supper was on the table. You probably now have the information you need but I find this chart and web calculator to be pretty handy.